Using Monte-Carlo simulations of X-ray flare distributions across the
accretion disk of active galactic nuclei (AGN), we obtain modeling results for
the energy-dependent fractional variability amplitude. Referring to previous
results of this model, we illustrate the relation between the shape of the
point-to-point fractional variability spectrum, F_pp, and the time-integrated
spectral energy distribution, F_E. The results confirm that the spectral shape
and variability of the iron Kalpha line are dominated by the flares closest to
the disk center.Comment: 2 pages, 1 figure, conference proceedings of the AGN meeting held in
October 2006 in Xi'an, China. To appear in "The Central Engine of Active
Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP
